JP2010252468A - Power transmission device and method, power receiving device and method, and power transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission system that ensures stable power transmission. <P>SOLUTION: A power transmission device 91 transmits power to a power-receiving device 92 employing a magnetic field resonance type power transmission technique. In this case, control is performed for changing the resonance frequency of a power-transmission side resonance circuit 101 of the power transmission device 91, and the resonance frequency of a power-receiving side resonance circuit 121 of the power-receiving device 92 so that the receiving power of the power receiving device 92 becomes a maximum. More specifically, control is performed for changing these resonance frequencies, by changing application voltages of a varicap diode 112 of the power-transmission side resonance circuit 101 and a varicap diode 132 of the power-receiving side resonance circuit 121. The present invention is applicable to, for example, power transmission systems. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power transmission device and method, a power reception device and method, and a power transmission system, and more specifically to a power transmission device and method, a power reception device and method, and a power transmission system that can stably transmit power without contact. About.

  In recent years, research and development of systems that transmit electric power in a non-contact manner have been performed (see, for example, Patent Document 1). Hereinafter, such a system is referred to as a non-contact power transmission system.

  As a power transmission method of such a non-contact power transmission system, for example, there is an electromagnetic induction power transmission method. In recent years, a magnetic field resonance type power transmission method exists as a power transmission method developed by a group of Prof. Soljacic of MIT (Massachusetts Institute of Technology). The magnetic field resonance type power transmission method has a feature that long-distance transmission is possible compared to the electromagnetic induction type power transmission method.

JP 2008-295191 A

  However, in the conventional magnetic field resonance type power transmission method, if a metal or a person approaches the coil that is a component of the non-contact power transmission system, for example, around a power transmission coil, a resonance coil, a power reception coil, etc., resonance occurs. The frequency sometimes changed. In the conventional magnetic field resonance type power transmission method, in particular, since the Q value of the resonance coil is very high, the transmission efficiency is lowered by a slight frequency change of the resonance frequency.

  As described above, it is difficult to stably transmit power with the conventional magnetic field resonance type power transmission method.

  This invention is made | formed in view of such a condition, and enables it to transmit electric power stably without contact.

  The power transmission device according to the first aspect of the present invention includes at least an oscillation unit and a resonance unit, and transmits a power to the power reception device according to a magnetic field resonance type power transmission method, an oscillation frequency of the oscillation unit, and the resonance unit And a control means for controlling the received power of the power receiving apparatus to be maximized by changing at least one of the resonance frequency of the power receiving apparatus.

  The control means receives the change command when a change command for changing at least one of the oscillation frequency and the resonance frequency is generated and transmitted by the power receiving device based on the received power. In accordance with the change command, control for changing at least one of the oscillation frequency and the resonance frequency can be performed.

  The resonance means is configured to change the resonance frequency, the change command is a command to change the resonance frequency, and the control means changes the resonance frequency according to the change command. Can do.

  The resonance means has a varicap, and the control means can change the resonance frequency by changing the voltage applied to the varicap.

  The oscillation means is configured to change the oscillation frequency, the change command is a command to change the oscillation frequency, and the control device changes the oscillation frequency according to the change command. Can do.

  The power transmission method according to the first aspect of the present invention is a method corresponding to the power transmission device according to the first aspect of the present invention.

  The power receiving device according to the first aspect of the present invention includes at least an oscillation unit and a power transmission side resonance unit. When the power is transmitted from a power transmission device that transmits power according to a magnetic resonance power transmission method, at least the power reception side A power receiving unit that receives the power using a resonance unit, and at least one of an oscillation frequency of the oscillation unit, a power transmission side resonance frequency of the power transmission side resonance unit, and a power reception side resonance frequency of the power reception side resonance unit is changed. Control means for controlling the received power in the power receiving means to be maximized.

  The power receiving side resonance means is configured to vary the power receiving side resonance frequency, and the control means measures the power receiving power and changes the power receiving side resonance frequency based on the measured value. Can do.

  The power-receiving-side resonance means has a varicap, and the control means can change the power-receiving-side resonance frequency by changing the voltage applied to the varicap.

  The power transmission side resonance means of the power transmission device is configured such that the power transmission side resonance frequency can be varied, and the control means further changes the power transmission side resonance frequency based on a measured value of the received power. It is possible to control to generate a change command to be transmitted and to transmit the change command to the power transmission device.

  The oscillating means of the power transmission device is configured such that the oscillation frequency can be varied, and the control means further generates a change command for changing the oscillating frequency based on a measured value of the received power. Thus, control for transmission to the power transmission device can be performed.

  The power receiving method according to the first aspect of the present invention is a method corresponding to the power receiving device according to the first aspect of the present invention.

  A power transmission system according to a first aspect of the present invention includes at least an oscillating unit and a power transmission side resonance unit, and transmits a power according to a magnetic field resonance type power transmission method, and the power transmitted from the power transmission device. A power receiving device that receives power using at least the power receiving side resonance means, and at least of the oscillation frequency of the oscillation means, the power transmission side resonance frequency of the power transmission side resonance means, and the power reception side resonance frequency of the power reception side resonance means By changing one, it is possible to control to maximize the received power in the power receiving apparatus.

  A power transmission device according to a second aspect of the present invention controls power reception power of the power reception device by changing power transmission means for transmitting power to the power reception device according to a magnetic field resonance type power transmission method, and power transmission power of the power transmission means. Control means.

  The power transmission method according to the second aspect of the present invention is a method corresponding to the power transmission device according to the second aspect of the present invention.

  A power receiving device according to a second aspect of the present invention includes a power receiving unit that receives power when the power is transmitted from a power transmitting device that transmits power according to a magnetic resonance power transmission method, and power transmission of the power transmitting device. Control means for controlling the received power of the power receiving device by changing the power.

  The power receiving method according to the second aspect of the present invention is a method corresponding to the power receiving device according to the second aspect of the present invention.

  A power transmission system according to a second aspect of the present invention includes: a power transmission device that transmits power according to a magnetic resonance power transmission method; and a power reception device that receives the power transmitted from the power transmission device. The received power of the power receiving device can be controlled by changing the transmitted power.

  In the first aspect of the present invention, at least the power transmitted from the power transmission device, the power transmission device transmitting power according to the magnetic field resonance type power transmission method using at least the oscillation means and the power transmission side resonance means, The following processing is executed by the power receiving device that receives power using the power receiving side resonance means. That is, at least one of the oscillation frequency of the oscillation means, the power transmission side resonance frequency of the power transmission side resonance means, and the power reception side resonance frequency of the power reception side resonance means is changed, so that the received power in the power reception device is Controlled to maximize.

  In the second aspect of the present invention, the following processing is executed by a power transmission device that transmits power according to a magnetic resonance power transmission method and a power reception device that receives the power transmitted from the power transmission device. Is done. The received power of the power receiving device is controlled by changing the transmitted power of the power transmitting device.

  According to the present invention, power can be stably transmitted.

It is a block diagram which shows the structural example of a basic power transmission system. It is a figure which shows an example of the change of the transmission efficiency of the basic power transmission system of FIG. It is a block diagram which shows the structural example of 1st Embodiment of the electric power transmission system with which this invention was applied. It is a flowchart explaining an example of the resonant frequency control process about the electric power transmission system of FIG. The relationship between the voltage applied to the power receiving side varicap in the power system of FIG. 3 and the output voltage value on the power receiving side is shown. It is a block diagram which shows the structural example of 2nd Embodiment of the electric power transmission system to which this invention was applied. It is a flowchart explaining an example of the oscillation frequency control process about the electric power transmission system of FIG. It is a figure explaining the outline of the transmission power variable method to which this invention is applied. It is a block diagram which shows the structural example of 2nd Embodiment of the electric power transmission system to which this invention was applied. It is a flowchart explaining an example of the transmission power control process about the power transmission system of FIG. It is a block diagram which shows the structural example of the hardware of the computer to which this invention was applied.

First, in order to facilitate understanding of the present invention and to clarify the background, a basic magnetic field resonance type power transmission method will be described. Next, three embodiments (hereinafter referred to as the first embodiment to the third embodiment, respectively) will be described as embodiments of the power transmission system to which the present invention is applied. Therefore, description will be given in the following order.
1. 1. Basic power transmission method First embodiment (example in which a resonant frequency variable technique is applied)
3. Second embodiment (example in which an oscillation frequency variable technique is applied)
4). Third embodiment (example in which transmission power variable method is applied)

<1. Basic power transmission method>
[Configuration example of power transmission system to which basic power transmission method is applied]

  FIG. 1 shows a configuration example of a power transmission system to which a basic power transmission method is applied (hereinafter referred to as a basic power transmission system).

  The basic power transmission system 11 includes a power transmission device 21 and a power reception device 22.

  The power transmission device 21 includes an oscillation circuit 31, a power transmission coil 32, and a power transmission side resonance circuit 33.

  For example, a power transmission coil 32 of about 1 loop is connected to the oscillation circuit 31. In the vicinity of the oscillation circuit 31 and the power transmission coil 32, for example, a power transmission side resonance circuit 33 composed of a coil of about several loops is arranged.

  The power receiving device 22 includes a power receiving side resonance circuit 51, a power receiving coil 52, a bridge rectifier circuit 53, and a smoothing capacitor 54.

  Similarly to the power transmission side resonance circuit 33, the power reception side resonance circuit 51 is constituted by, for example, a coil of about several loops. A power receiving coil 52 is arranged in the vicinity of the power receiving side resonance circuit 51. The power receiving coil 52 is configured by, for example, a coil of about one loop.

  A bridge rectifier circuit 53 is connected to the power receiving coil 52. Since the frequency of the alternating current flowing through the bridge rectifier circuit 53 is relatively high, it is preferable to employ a fast recovery diode or the like for the bridge rectifier circuit 53.

  Smoothing capacitors 54 are connected to both ends of the output of the bridge rectifier circuit 53. The smoothing capacitor 54 is composed of, for example, an electrolytic capacitor.

  The operation of the basic power transmission system 11 having such a configuration is as follows.

  That is, when the oscillation circuit 31 of the power transmission device 21 starts an oscillation operation, the oscillation circuit 31 outputs an alternating current with a predetermined frequency f31 (hereinafter referred to as an oscillation frequency f31). The alternating current output from the oscillation circuit 31 flows to the power transmission coil 32, and as a result, an oscillating electromagnetic field having an oscillation frequency f 31 is generated around the power transmission coil 32.

  An alternating current flows through the power transmission side resonance circuit 33 by being induced by the oscillating electromagnetic field of the power transmission coil 32. As a result, an oscillating electromagnetic field having a resonance frequency f33 represented by the following equation (1) is generated around the power transmission side resonance circuit 33.

  That is, as shown in FIG. 1, the equivalent circuit of the power transmission side resonance circuit 33 is an LC circuit including a coil inductance Ls and a stray capacitance Cs. In this case, the resonance frequency f33 of the power transmission side resonance circuit 33 is expressed by the following equation (1).

・・・（１）

... (1)

  In the power reception side resonance circuit 51, an alternating current is induced by the vibration electromagnetic field of the power transmission side resonance circuit 33, and as a result, the vibration electromagnetic field having the resonance frequency f 51 represented by the following equation (2) is generated around the power reception side resonance circuit 51. Occurs.

  That is, the equivalent circuit of the power receiving side resonance circuit 51 is an LC circuit composed of the coil inductance Lr and the stray capacitance Cr, as shown in FIG. In this case, the resonance frequency f51 of the power receiving side resonance circuit 51 is expressed by the following equation (2).

・・・（２）

... (2)

  Ideally, the resonance frequency f33 of the power transmission side resonance circuit 33 and the resonance frequency f51 of the power reception side resonance circuit 51 are the same as the oscillation frequency f31, respectively. Here, the reason that “ideally” is described is that the resonance frequencies f33 and f51 may be different from the oscillation frequency f31 during actual use. However, the details of this will be described later in the item [About transmission efficiency of basic power transmission method].

  An alternating current flows from the power receiving coil 52 to the bridge rectifier circuit 53 by being induced by the oscillating electromagnetic field of the power receiving side resonance circuit 51. This alternating current is full-wave rectified in the bridge rectifier circuit 53. The full-wave rectified current (pulsating current) is converted into a direct current by the smoothing capacitor 54 and supplied to a subsequent circuit (not shown).

  In this manner, in the basic power transmission system 11, power is supplied from the power transmission device 21 to the power reception device 22 in a contactless manner.

[Transmission efficiency of basic power transmission method]

  By the way, in the basic power transmission method, the transmission efficiency cannot be increased unless the Q value of the resonance circuit is increased. That is, in the example of FIG. 1, it is necessary to increase the Q value of the resonance circuit 33 on the transmission side and the resonance circuit 51 on the power reception side.

  Note that, at a frequency that is used in the basic power transmission method, the Q value of the resonance circuit depends on the characteristics of the coil, and is expressed as the following equation (3).

・・・（３）

... (3)

  In equation (3), ω represents the angular frequency, L represents the inductance value of the coil of the resonance circuit, and R represents the resistance value of the resonance circuit. That is, as ω and L, the parameter of the above-described equation (1) is used for the resonance circuit 33 on the power transmission side, and the parameter of the above-described equation (2) is used for the resonance circuit 51 on the power reception side.

  However, the resonance frequencies f33 and f51 of the resonance circuits 33 and 51 having a high Q value are generally easily affected by surrounding metals, people, temperature, humidity, and the like.

  As described above, ideally, the resonance circuits 33 and 51 are designed so that the resonance frequencies f33 and f51 coincide with the oscillation frequency f31. However, it is difficult to mass-produce the resonance circuits 33 and 51 in which the resonance frequencies f33 and f51 coincide with the oscillation frequency f31 with high accuracy.

  From the above, the resonance frequencies f33 and f51 during use of the resonance circuits 33 and 51 may be different from the oscillation frequency f31. In such a case, transmission efficiency will deteriorate. This will be described in detail with reference to FIG.

  FIG. 2 is a diagram illustrating an example of a change in transmission efficiency of the basic power transmission system 11.

  In FIG. 2, the vertical axis represents the attenuation [dB] with respect to the maximum transmission efficiency as the transmission efficiency, and the horizontal axis represents the oscillation frequency f31 [MHz].

  In the example of FIG. 2, the resonance frequencies f33 and f51 are fixed to 13.56 MHz which is an ISM (Industry Science Medical) band. In the prototype experiment, the Q values of the resonance circuits 33 and 51 were both about 400. That is, the Q value is set to a very high value.

  As can be seen from FIG. 2, even if the oscillation frequency f31 is slightly shifted from the resonance frequencies f33 and f51 (= 13.56 MHz) to about 0.5 MHz, the transmission efficiency is significantly reduced to about 20 dB. From the opposite viewpoint, when the oscillation frequency f31 is fixed, if the resonance frequency f33, f51 changes even slightly due to the proximity of metal or humans, the transmission efficiency is greatly reduced. It means to end up. A significant decrease in transmission efficiency means that almost no power can be transmitted.

<2. First Embodiment>

  Accordingly, the present inventors have invented a method for changing the resonance frequency based on the basic power transmission method. Hereinafter, this method is referred to as a resonance frequency variable method. Of the power transmission system to which the present invention is applied, an embodiment to which such a resonance frequency variable technique is applied is the first embodiment.

  That is, in the first embodiment, the resonance frequency variable method is applied, and the resonance frequency is controlled to coincide with the oscillation frequency even when the power transmission system is used. As a result, it is possible to prevent a decrease in transmission efficiency, that is, to stably transmit power without contact.

  Hereinafter, details of the first embodiment will be further described.

[Configuration Example of First Embodiment of Power Transmission System]

  FIG. 3 shows a configuration example of the first embodiment of the power transmission system to which the present invention is applied.

  3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The power transmission system 81 in the example of FIG. 3 is configured to include a power transmission device 91 and a power reception device 92.

  As in the case of FIG. 1, the power transmission device 91 is provided with an oscillation circuit 31 and a power transmission coil 32. The power transmission device 91 is also provided with a power transmission side resonance circuit 101 instead of the power transmission side resonance circuit 33 of FIG.

  The power transmission side resonance circuit 101 is connected to a series circuit composed of a varicap 112 and a capacitor 113 in parallel with the power transmission side resonance circuit 33 (a coil of several loops) in FIG.

  Here, when the capacitance value of the varicap 112 is described as Cvs and the capacitance value of the capacitor 113 is described as Ccs, the resonance frequency f101 of the power transmission side resonance circuit 101 is expressed by the following equation (4).

・・・（４）

... (4)

  In Expression (4), the capacitance value Ccs of the capacitor 113 is a predetermined fixed value, whereas the capacitance value Cvs of the varicap 112 is a variable value. This is because the varicap 112 is an element also called a varactor or a variable capacitance diode, and has a characteristic that the capacitance value Cvs decreases as the applied voltage increases.

  That is, since the capacitance value Cvs is changed by changing the voltage applied to the varicap 112, the resonance frequency f101 of the power transmission side resonance circuit 101 can be changed as a result. Therefore, by changing the resonance frequency f101 of the power transmission side resonance circuit 101 so as to coincide with the oscillation frequency f33, it is possible to prevent a decrease in transmission efficiency, that is, to stably transmit power without contact. Become.

  In other words, in order to change the resonance frequency f101 of the power transmission side resonance circuit 101 to coincide with the oscillation frequency f33, appropriate control of the capacitance value Cvs of the varicap 112, that is, appropriate application voltage of the varicap 112 is appropriate. It is preferable to perform control. Therefore, in order to realize such control (hereinafter referred to as power transmission side resonance frequency variable control), the power transmission device 91 is further provided with an antenna 102, a reception circuit 103, and a D / A (Digital to Analog) conversion circuit 104. ing.

  The receiving circuit 103 receives the control data transmitted from the power receiving device 92 via the antenna 102. Although details will be described later, this control data includes a command for changing the voltage applied to the varicap 112 and the like.

  Therefore, the receiving circuit 103 generates a command (digital data) for the voltage applied to the varicap 112 based on the control data, and supplies the command to the D / A conversion circuit 104. The D / A conversion circuit 104 changes the voltage applied to the varicap 112 in accordance with a command from the reception circuit 103. That is, the D / A conversion circuit 104 applies an analog voltage corresponding to the digital data (command) from the reception circuit 103 to the varicap 112.

  Thereby, the capacitance value Cvs of the varicap 112 is changed, and as a result, the resonance frequency f101 of the power transmission side resonance circuit 101 changes.

  As described above, the power transmission side resonance frequency variable control is executed based on the control data transmitted from the power receiving device 92. Details of the power transmission side resonance frequency variable control will be described later with reference to FIG.

  For such a power transmission device 91, the power reception device 92 is provided with a power reception coil 52, a bridge rectifier circuit 53, and a smoothing capacitor 54 as in the case of FIG. 1. In addition, the power receiving device 92 is provided with a power receiving side resonance circuit 121 instead of the power receiving side resonance circuit 51 of FIG.

  The power receiving side resonance circuit 121 is connected to a series circuit including a varicap 132 and a capacitor 133 in parallel with the power receiving side resonance circuit 51 (a coil of several loops) in FIG.

  Here, when the capacitance value of the varicap 132 is described as Cvr and the capacitance value of the capacitor 133 is described as Ccr, the resonance frequency f121 of the power-receiving-side resonance circuit 121 is expressed by the following equation (5).

・・・（５）

... (5)

  In the equation (5), for the same reason as the above equation (4), the capacitance value Ccr of the capacitor 133 is a predetermined fixed value, whereas the capacitance value Cvr of the varicap 132 is a variable value. This is because the varicap 132 is an element also called a varactor or a variable capacitance diode, and has a characteristic that the capacitance value Cvr decreases as the applied voltage increases.

  That is, by changing the voltage applied to the varicap 132, the capacitance value Cvr changes, and as a result, the resonance frequency f121 of the power receiving side resonance circuit 121 can be changed. As a result, by changing the resonance frequency f121 of the power reception side resonance circuit 121 to coincide with the oscillation frequency f33, it is possible to prevent a decrease in transmission efficiency, that is, to stably transmit power without contact. become.

  In other words, in order to change the resonance frequency f121 of the power reception side resonance circuit 121 to coincide with the oscillation frequency f33, appropriate control of the capacitance value Cvr of the varicap 132, that is, appropriate application voltage of the varicap 132 is appropriate. It is preferable to perform control. Therefore, in order to realize such control (hereinafter referred to as power-receiving-side resonance frequency variable control), the power receiving device 92 is further provided with an A / D conversion circuit 122, a microcomputer 123, and a D / A conversion circuit 124. Yes.

  The A / D conversion circuit 122 converts the analog voltage at both ends of the smoothing capacitor 54 into an output voltage value V that is digital data, and supplies it to the microcomputer 123.

  The microcomputer 123 controls the entire operation of the power receiving device 92.

  For example, the microcomputer 123 generates a command (digital data) of the voltage applied to the varicap 132 on the power receiving side based on the output voltage value V of the A / D conversion circuit 12 and supplies the command to the D / A conversion circuit 124. .

  The D / A conversion circuit 124 changes the voltage applied to the varicap 132 in accordance with a command from the microcomputer 123. That is, the D / A conversion circuit 124 applies an analog voltage corresponding to the digital data (command) from the microcomputer 123 to the varicap 132.

  As a result, the capacitance value Cvr of the varicap 132 is changed, and as a result, the resonance frequency f121 of the power receiving side resonance circuit 121 changes.

  Thus, the power receiving side resonance frequency variable control is executed based on the output voltage value V of the A / D conversion circuit 12. The details of the power receiving side resonance frequency variable control will be described later with reference to FIG.

  Further, for example, the microcomputer 123 generates control data including an instruction to change the voltage applied to the transmission-side varicap 112 based on the output voltage value V of the A / D conversion circuit 12.

  As described above, this control data is used for power transmission side resonance frequency variable control. Therefore, this control data needs to be transferred to the power transmission device 91. For this reason, the power receiving apparatus 92 is further provided with a transmission circuit 125 and an antenna 126.

  That is, the control data generated by the microcomputer 123 is supplied to the transmission circuit 125. Therefore, the transmission circuit 125 transmits the control data from the microcomputer 123 to the power transmission device 91 via the antenna 126. Then, as described above, the power transmission device 91 changes the voltage applied to the varicap 112 on the power transmission side using this control data. As a result, the capacitance value Cvs changes, and the resonance frequency f101 of the power transmission side resonance circuit 101 changes. In this way, power transmission side resonance frequency variable control is executed. Further details of the power transmission side resonance frequency variable control will be described later with reference to FIG.

[Operation Example of First Embodiment of Power Transmission System]

  Next, an operation example of the power transmission system 81 in the example of FIG. 3 will be described.

  However, among the operations of the power transmission system 81, the power transmission operation itself from the power transmission device 91 to the power reception device 92 is basically the same as the operation of the basic power transmission system 11 of FIG. Is omitted.

  Therefore, a process (hereinafter referred to as a resonance frequency control process) for realizing the power receiving side resonance frequency variable control and the power transmission side resonance frequency variable control in the operation of the power transmission system 81 will be described below.

  The power supplied from the power transmitting device 91 to the power receiving device 92 is hereinafter referred to as “received power”, and when the received power is described as P, the received power P is expressed by the following equation (6).

・・・（６）

... (6)

  In Equation (6), R represents the resistance value of the load of the power receiving device 92.

  Here, the power transmission side resonance frequency variable control and the power reception side resonance frequency variable control are controls in which the resonance frequencies f101 and f121 are changed to coincide with the oscillation frequency f33. As described with reference to FIG. 2 described above, when the resonance frequencies f101 and f121 match the oscillation frequency f33, the transmission efficiency is the highest, and thus the received power P is maximum. That is, as power transmission side resonance frequency variable control and power reception side resonance frequency variable control, control for changing the resonance frequencies f101 and f121 so as to maximize the received power P may be employed. Furthermore, as shown in the equation (6), if the load is fixed, the resistance value R of the load is constant, and the received power P is proportional to the square of the output voltage value V. Therefore, as power reception-side resonance frequency variable control, control for changing the resonance frequencies f101 and f121 so as to maximize the output voltage value V may be employed. An example of a resonance frequency control process for realizing such a power receiving side resonance frequency variable control and a power transmission side resonance frequency variable control is shown in FIG.

  FIG. 4 is a flowchart for explaining an example of the resonance frequency control process.

  In step S11, the microcomputer 123 increases the command of the voltage applied to the power receiving side varicap 132 by one step, and measures each output voltage value V for each step.

  In step S <b> 12, the microcomputer 123 sets a command when the output voltage value V is maximum as the optimum command for the power receiving side varicap 132.

  Thereafter, the microcomputer 123 continues to output the optimum command (digital data) to the D / A conversion circuit 124. As a result, the resonance frequency f121 of the power receiving side resonance circuit 121 becomes a frequency at which the output voltage value V becomes maximum, that is, a frequency that substantially matches the oscillation frequency f33.

  More specifically, for example, when the applied voltage of the varicap 132 increases, the capacitance value Cvr of the varicap 132 decreases as described above, and the power receiving side resonance circuit 121 is expressed by the above-described equation (5). The resonance frequency f121 becomes higher. On the contrary, when the voltage applied to the varicap 132 decreases, the capacitance value Cvr of the varicap 132 increases as described above, and the resonance frequency f121 of the power reception side resonance circuit 121 as shown in the above equation (5). Becomes lower.

  Therefore, in order to make the resonance frequency f121 of the power reception side resonance circuit 121 substantially coincide with the oscillation frequency f33, it is necessary to be able to adjust the resonance frequency f121 both in the high direction and in the low direction. That is, even when a metal or a person is in proximity, the capacitance value Cvr of the varicap 132 that maximizes the received power P falls within the variable range so that the capacitance value Cvr of the varicap 132 decreases in the increasing direction. It is necessary to be able to adjust the direction. Furthermore, since the varicap 132 has variations in characteristics, it is necessary to be able to make adjustments in consideration of such variations.

  In order to enable such adjustment, when the capacitance value Cvr of the varicap 132 becomes an intermediate capacitance value within the variable range, the resonance frequency f121 in an ideal state in which no metal or human is in close proximity is obtained. The target frequency (oscillation frequency f33) is preferable. Thus, for example, in this embodiment, the inductance Lr of the coil of the power reception side resonance circuit 121 and the capacitance Ccr of the capacitor 133 are adjusted so as to be so.

  Therefore, for example, in this embodiment, when the command of the voltage applied to the power receiving side varicap 132 is increased step by step in the process of step S11, the output voltage is determined at a specific step until the command of the highest step is reached. The value V should be maximized. For example, in an ideal state where no metal or human is in close proximity, the output voltage value V should be maximized in almost the middle step of the variable range of the applied voltage command of the varicap 132 on the power receiving side. . Further, for example, in the state where a metal or a person is in close proximity, the output voltage value V should be maximized at a step slightly deviated before and after the intermediate step.

  For example, FIG. 5 shows the relationship between the voltage applied to the varicap 132 on the power receiving side and the output voltage value V.

  In FIG. 5, the vertical axis represents the output voltage value V. The horizontal axis represents the voltage applied to the varicap 132 on the power receiving side.

  In the example of FIG. 5, the output voltage value V changes in a mountain shape, the applied voltage of the varicap 132 on the power receiving side is about 10 V, and is at the top of the mountain, that is, the output voltage value V is maximized. You can see that

  Therefore, in the process of step S12, a command (digital data) when the output voltage value V is maximum, and a command of a step of about 10 V in the example of FIG. 5 is set as the optimum command for the varicap 132 on the power receiving side. It is done.

  Thus, the power receiving side resonance frequency variable control is realized by the processing of steps S11 and S12.

  Next, power transmission side resonance frequency variable control is realized by the processing after step S13.

  That is, in step S13, the microcomputer 123 increases the command of the voltage applied to the power transmission side varicap 112 step by step, and measures each output voltage value V for each step.

  Specifically, for example, the microcomputer 123 generates control data including a change command for increasing the command of the voltage applied to the varicap 112 on the power transmission side by one step and transmits the control data via the transmission circuit 125 and the antenna 126. Send to. Then, as described above, the power transmission device 91 increases the applied voltage of the power transmission side varicap 112 by one step according to the control data. As a result, the capacitance value Cvs changes and the resonance frequency f101 of the power transmission side resonance circuit 101 changes. As a result, the output voltage value V of the power receiving device 92 changes. Therefore, the microcomputer 123 measures the changed output voltage value V. As a process in step S13, such a series of processes is executed for each step.

  Note that, for the same reason as the varicap 132 on the power transmission side, when the capacitance value Cvs of the varicap 112 becomes an intermediate capacitance value in the variable range, in an ideal state where metal or a person is not in proximity. The resonance frequency f101 is preferably the target frequency (oscillation frequency f33). Thus, for example, in this embodiment, the inductance Ls of the coil of the power transmission side resonance circuit 101 and the capacitance Ccs of the capacitor 133 are adjusted so as to be so.

  In step S <b> 14, the microcomputer 123 sets a command when the output voltage value V is maximum as the optimum command for the varicap 112 on the power transmission side.

  Specifically, for example, the microcomputer 123 generates control data including an instruction for setting an optimum command for the voltage applied to the varicap 112 on the power transmission side, and transmits the control data to the power transmission apparatus 91 via the transmission circuit 125 and the antenna 126. To do.

  Then, the power transmission device 91 continues to apply the applied voltage according to the optimum command to the varicap 112 on the power transmission side. As a result, the resonance frequency f101 of the power transmission side resonance circuit 101 becomes a frequency at which the output voltage value V is maximum, that is, a frequency that substantially matches the oscillation frequency f33.

  Thus, in the power transmission system 81 of the first embodiment, the resonance frequency control process is executed. As a result, the resonance frequency is automatically controlled so that the received power P is maximized. As a result, power can be stably supplied from the power transmission device 91 to the power reception device 92.

  This does not change even if the resonance frequencies f101 and f121 vary. That is, in the power transmission system 81 of the first embodiment, since the resonance frequency control process is executed, variations in the resonance frequencies f101 and f121 are allowed. As a result, it is possible to easily mass-produce the power transmission system 81 of the first embodiment as compared with the contactless power system to which the conventional magnetic field resonance type power transmission method is applied. That is, in the non-contact power system to which the conventional magnetic field resonance type power transmission method is applied, the resonance frequency control process cannot be executed, and therefore, variations in the resonance frequency cannot be allowed. However, it is difficult to suppress the manufacturing variation of the resonance frequency, and as a result, it is difficult to mass-produce a non-contact power system to which the conventional magnetic field resonance type power transmission method is applied. This difficulty is eliminated because the power transmission system 81 of the first embodiment allows variations in the resonance frequencies f101 and f121.

  Note that the start timing of the resonance frequency control process of FIG. 4 is not particularly limited. For example, a timing at which the power receiving device 92 is energized can be employed as the start timing. In addition, for example, a timing at which the output voltage value V decreases, a timing at which a predetermined time has elapsed, a timing instructed by the user, or the like can be employed as the start timing.

  Also, in the resonance frequency control process, two controls of the power receiving side resonance frequency variable control and the power transmission side resonance frequency variable control are realized. However, only one of these two controls can be performed. For example, when one of the power transmission side resonance circuit 101 and the power reception side resonance circuit 121 is arranged at a place where humans and metals are not close to each other and is not affected by them, only the resonance frequency of the other is controlled. May be.

  Further, from the viewpoint of realizing the power receiving side resonance frequency variable control and the power transmission side resonance frequency variable control, those control methods may be any methods that can control the resonance frequency so that the received power P is maximized. The method is not particularly limited.

  For example, as a method for changing the resonance frequency (hereinafter referred to as a resonance frequency variable method), in the above-described example, a method of changing the voltage applied to the varicaps 112 and 113 is employed. However, the resonance frequency variable method is not particularly limited to the above-described example. For example, a method of changing the inductance L and capacitance C of the resonance circuit using an element other than the varicap and a motor-driven variable capacitor (variable resistor) is used. Can be adopted. In addition, for example, a method of changing the inductance L can be adopted by changing the coil core in and out of the resonance circuit, changing the coil interval, or electrically switching the coil tapping.

<3. Second Embodiment>

  Furthermore, from the viewpoint of maximizing the transmission efficiency, that is, from the viewpoint of maximizing the received power P, it is sufficient to perform control so that the resonance frequency and the oscillation frequency coincide with each other.

  In other words, in the first embodiment, as the control for matching the resonance frequency and the oscillation frequency f31 by changing the resonance frequency while fixing the oscillation frequency, the power receiving side resonance frequency variable control and the power transmission side resonance frequency variable control are performed. Adopted.

  However, from the viewpoint of maximizing the received power P, it is also possible to realize a control for matching the resonance frequency and the oscillation frequency by fixing the resonance frequency and changing the oscillation frequency. Hereinafter, such control is referred to as oscillation frequency variable control.

  In other words, the present inventors have invented a technique (hereinafter referred to as an oscillation frequency variable technique) that realizes an oscillation frequency variable control in addition to the resonance frequency change technique as a technique based on the basic power transmission technique. Of the power transmission system to which the present invention is applied, an embodiment to which such an oscillation frequency variable technique is applied is a second embodiment.

  That is, in the second embodiment, the oscillation frequency variable method is applied, and the oscillation frequency f31 is controlled to coincide with the resonance frequency even during use of the power transmission system. As a result, it is possible to prevent a decrease in transmission efficiency, that is, to stably transmit power without contact.

  The details of the second embodiment will be further described below.

[Configuration Example of Second Embodiment of Power Transmission System]

  FIG. 6 shows a configuration example of the second embodiment of the power transmission system to which the present invention is applied.

  In FIG. 6, the same reference numerals are given to the portions corresponding to those in FIG. 1 or FIG.

  The power transmission system 161 in the example of FIG. 6 is configured to include a power transmission device 171 and a power reception device 172.

  From the viewpoint of comparison with FIG. 1, the power transmission device 171 is provided with a power transmission coil 32 and a power transmission side resonance circuit 33 as in the case of FIG. 1. The power transmission device 171 is also provided with an oscillation circuit 181 instead of the oscillation circuit 31 of FIG. The power transmission device 171 is further provided with an antenna 102 and a receiving circuit 103.

  From the viewpoint of comparison with FIG. 3, the power transmission device 171 is provided with an oscillation circuit 181 instead of the oscillation circuit 31 of FIG. 3, and is replaced with the power transmission side resonance circuit 101 of FIG. The power transmission side resonance circuit 33 is provided. Similarly to the case of FIG. 3, the power transmission device 171 is provided with a power transmission coil 32, an antenna 102, and a reception circuit 103. On the other hand, as a component of the power transmission device 171, the D / A conversion circuit 104 which is one of the components of the power transmission device 91 in FIG. 3 is omitted.

  The oscillation circuit 181 is configured to include a reference frequency generation circuit 191, a phase synchronization circuit 192, and an amplification circuit 193 in order to vary the oscillation frequency f181.

  The reference frequency generation circuit 191 generates an electric signal having a reference frequency and supplies it to the phase synchronization circuit 192. The phase synchronization circuit 192 is configured by, for example, a PLL (Phase-locked loop) circuit. In the phase synchronization circuit 192, a reference frequency magnification N (N is a numerical value of 1 or more) is set. In other words, the phase synchronization circuit 192 generates an electrical signal having a frequency N times the reference frequency by performing predetermined processing on the electrical signal having the reference frequency, and supplies the electrical signal to the amplifier circuit 193. The amplifier circuit 193 amplifies the output signal of the phase synchronization circuit 192 and outputs the amplified electric signal. The output signal of the amplifier circuit 193 is the output signal of the oscillation circuit 181.

  In this way, the oscillation frequency f181 of the oscillation circuit 181 is N times the reference frequency. That is, the oscillation frequency f181 can be changed by changing the setting of the N value of the phase synchronization circuit 192.

  The N value of the phase synchronization circuit 192 is set by the reception circuit 103. That is, the receiving circuit 103 receives the control data transmitted from the power receiving device 172 via the antenna 102. Although details will be described later, this control data includes an N value change command and the like. Therefore, the receiving circuit 103 changes the setting of the N value of the phase synchronization circuit 192 based on the control data.

  As described above, the oscillation frequency variable control is executed based on the control data transmitted from the power receiving apparatus 172. Further details of the oscillation frequency variable control will be described later with reference to FIG.

  With respect to the power transmission device 171 having such a configuration, the configuration of the power reception device 172 is as follows from the viewpoint of comparison with FIG. That is, the power receiving device 172 is provided with the power receiving side resonance circuit 51, the power receiving coil 52, the bridge rectifier circuit 53, and the smoothing capacitor 54, as in the case of FIG. The power receiving device 172 further includes an A / D conversion circuit 122, a microcomputer 123, a D / A conversion circuit 124, a transmission circuit 125, and an antenna 126.

  From the viewpoint of comparison with FIG. 3, the power receiving device 172 is provided with a power receiving side resonance circuit 51 similar to that in FIG. 1 instead of the power receiving side resonance circuit 121 of FIG. 3. Further, as a component of the power receiving device 172, the D / A conversion circuit 124 which is one of the components of the power receiving device 92 in FIG. 3 is omitted. Other configurations of the power receiving device 172 are the same as those in FIG.

[Operation Example of Second Embodiment of Power Transmission System]

  Next, an operation example of the power transmission system 161 in the example of FIG. 6 will be described.

  However, among the operations of the power transmission system 161, the power transmission operation itself from the power transmission device 171 to the power reception device 172 is basically the same as the operation of the basic power transmission system 11 of FIG. Is omitted.

  Therefore, a process for realizing the oscillation frequency variable control (hereinafter referred to as an oscillation frequency control process) in the operation of the power transmission system 161 will be described below.

  FIG. 7 is a flowchart for explaining an example of the oscillation frequency control process.

  In step S31, the microcomputer 123 increases the N value on the power transmission side by one step and measures each output voltage value V for each step.

  Specifically, for example, the microcomputer 123 generates control data including a change command that increases the N value on the power transmission side by one step, and transmits the control data to the power transmission device 171 via the transmission circuit 125 and the antenna 126. Then, as described above, power transmission device 171 increases the N value of phase synchronization circuit 192 by one step according to the control data. As a result, the oscillation frequency f181 of the oscillation circuit 181 changes, and as a result, the output voltage value V of the power receiving device 172 changes. Therefore, the microcomputer 123 measures the changed output voltage value V. As a process of step S31, such a series of processes is executed for each step.

  In step S <b> 32, the microcomputer 123 sets the command when the output voltage value V is maximum as the optimum command for the N value on the power transmission side.

  Specifically, for example, the microcomputer 123 generates control data including an N-value optimum command setting command on the power transmission side, and transmits the control data to the power transmission device 171 via the transmission circuit 125 and the antenna 126.

  Then, the power transmission device 171 sets the step value according to the optimum command as the N value of the phase synchronization circuit 192. As a result, the oscillation frequency f181 of the oscillation circuit 181 is a frequency at which the output voltage value V is maximized, that is, a frequency that substantially matches the resonance frequency f33 of the transmission side resonance circuit 33 and the resonance frequency f51 of the power reception side resonance circuit 51. .

  Thus, in the power transmission system 161 of the second embodiment, the oscillation frequency control process is executed. As a result, the oscillation frequency is automatically controlled so that the received power P is maximized. As a result, power can be stably supplied from the power transmission device 171 to the power reception device 172. For the same reason as in the first embodiment, the power transmission system 161 of the second embodiment can also be easily mass-produced.

<4. Third Embodiment>

  By the way, in 1st Embodiment and 2nd Embodiment mentioned above, the distance (henceforth a transmission distance) between the power transmission side and the power receiving side was fixed. However, for example, when the power receiving device is configured by a portable terminal or the like and is portable, the transmission distance may change.

  In this case, the received power P changes in inverse proportion to the transmission distance. Therefore, if no measures are taken when the transmission distance is variable, for example, when the transmission distance is short, the received power P is greater than or equal to the power required on the power receiving side (hereinafter referred to as necessary power). Unnecessary radiation may increase or wasteful power may be consumed. On the other hand, when the transmission distance is long, the received power P becomes less than the required power, which may hinder the operation on the power receiving side.

  That is, it is preferable to maintain the received power P with the required power. However, if no measures are taken when the transmission distance varies, it is difficult to maintain the received power P with the required power.

  Therefore, the present inventors have invented a method for controlling the output power (hereinafter referred to as transmitted power) of the power transmission device 91 based on the basic power transmission method in order to maintain the received power P with the necessary power. Hereinafter, such control is referred to as transmission power variable control, and such a method is referred to as a transmission power variable method.

[Transmission power variable method]

  FIG. 8 is a diagram illustrating a transmission power variable method.

  In FIG. 8, the vertical axis represents the received power P, and the horizontal axis represents the transmission distance.

  In the example of FIG. 8, for the sake of simplicity, it is assumed that the transmission power can be varied in three stages of “low”, “medium”, and “high”. In this case, a change in the received power P with respect to the transmission distance when the transmission voltage is “low” is indicated by a curve PP1. A change in the received power P with respect to the transmission distance when the transmitted power is “medium” is indicated by a curve PP2. A change in the received power P with respect to the transmission distance when the transmitted power is “high” is indicated by a curve PP3.

  Now, for example, assume that the transmission distance is the distance D2 and the transmitted power is “medium”. In this case, the received power P is required power. That is, when the transmission distance is the distance D2, it is preferable that the transmission power is controlled to be “medium”.

  However, for example, when the transmission distance subsequently changes to a relatively short distance D1, if the transmission power is maintained at “medium”, the received power P exceeds the required power. Therefore, in such a case, as the transmission power variable control, control for changing the transmission power from “medium” to “low” is executed, and as a result, the received power P can be maintained as it is.

  Further, for example, when the transmission distance subsequently changes to a relatively long distance D3, the received power P will be less than the required power if the transmitted power is kept “low”. Therefore, in such a case, control for changing the transmission power from “low” to “high” is executed as the transmission power variable control, and as a result, the received power P can be maintained as it is.

  Of the power transmission system to which the present invention is applied, an embodiment to which such a variable transmission power technique is applied is a third embodiment.

  That is, in the third embodiment, the transmission power variable method is applied, and the received power P is controlled to maintain the required power regardless of the transmission distance. As a result, power can be stably transmitted without contact.

  Hereinafter, details of the third embodiment will be further described.

[Configuration Example of First Embodiment of Power Transmission System]

  FIG. 9 shows a configuration example of a third embodiment of the power transmission system to which the present invention is applied.

  9, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The power transmission system 221 in the example of FIG. 9 is configured to include a power transmission device 231 and a power reception device 232.

  As in the case of FIG. 1, the power transmission device 231 is provided with an oscillation circuit 31, a power transmission coil 32, and a power transmission side resonance circuit 33. Further, the power transmission device 91 is provided with an amplifier circuit 241 between the oscillation circuit 31 and the power transmission coil 32. Furthermore, the power transmission apparatus 91 is provided with a transmission power control circuit 242, a microcomputer 243, a reception circuit 244, and an antenna 245.

  As in the case of FIG. 1, the power receiving device 232 includes a power receiving side resonance circuit 51, a power receiving coil 52, a bridge rectifier circuit 53, and a smoothing capacitor 54. Further, the power receiving device 232 is provided with an A / D conversion circuit 251 at the subsequent stage. Furthermore, the power receiving device 232 is provided with a microcomputer 252, a transmission circuit 253, and an antenna 254.

  The A / D conversion circuit 251 on the power reception device 232 side converts the analog voltage at both ends of the smoothing capacitor 54 into an output voltage value V that is digital data, and supplies it to the microcomputer 123.

  The microcomputer 252 on the power receiving device 232 side controls the entire operation of the power receiving device 232. For example, the microcomputer 252 generates control data including a transmission power change command and the like based on the output voltage value V of the A / D conversion circuit 251 and supplies the control data to the transmission circuit 253.

  The transmission circuit 125 on the power reception device 232 side transmits control data from the microcomputer 252 to the power transmission device 231 via the antenna 254.

  The reception circuit 244 on the power transmission device 231 side receives the control data transmitted from the power reception device 232 via the antenna 245 and supplies the control data to the microcomputer 243.

  The microcomputer 243 on the power transmission device 231 side controls the entire operation of the power transmission device 231. For example, the microcomputer 243 generates a transmission power change instruction based on the control data, and supplies the transmission power change instruction to the transmission power control circuit 242.

  The transmission power control circuit 242 sets the gain (amplification factor) of the amplifier circuit 241 in accordance with a transmission power change command. The amplification circuit 241 amplifies the output signal of the oscillation circuit 31 by a set gain.

  When a value lower than the pre-setting value is set as the gain, “amplify by the set gain” means that the level of the output signal of the oscillation circuit 31 is lowered, and that much This means that the transmitted power will be lower. On the other hand, when a value higher than the value before setting is set as the gain, “amplify by the set gain” means that the level of the output signal of the oscillation circuit 31 rises, This means that the transmission power increases by the amount. Further, when the same value as the value before setting is set as the gain (when the gain setting is not changed), “amplification by the set gain” means that the output signal of the oscillation circuit 31 is This means that the level is maintained, and as a result, the transmission power is also maintained as it is.

[Example of Operation of Third Embodiment of Power Transmission System]

  Next, an operation example of the power transmission system 221 in the example of FIG. 9 will be described.

  However, among the operations of the power transmission system 221, the power transmission itself from the power transmission device 231 to the power reception device 232 is basically the same as the operation of the basic power transmission system 11 of FIG. Is omitted.

  Therefore, a process for realizing the transmission power variable control (hereinafter referred to as a transmission power control process) in the operation of the power transmission system 221 will be described below.

  FIG. 10 is a flowchart illustrating an example of the transmission power control process.

  In step S51, the microcomputer 252 measures the output voltage value V.

  In step S52, the microcomputer 252 determines whether or not the output voltage value V is an appropriate value corresponding to the required power (hereinafter referred to as an appropriate value).

  If the output voltage value V is an appropriate value, it is determined as YES in step S52, the process returns to step S51, and the subsequent processes are repeated. That is, as long as the output voltage value V is an appropriate value, the loop processing of steps S51 and S52 is repeatedly executed, and the transmission power is maintained as it is.

  Thereafter, when the output voltage V exceeds or falls below an appropriate value due to a change in the transmission distance or the like, it is determined in step S52 that the output voltage value V is not an appropriate value, and the process proceeds to step S53. .

  In step S53, the microcomputer 252 determines whether or not the output voltage value V exceeds an appropriate value.

  When the output voltage value V is below the appropriate value, it is determined as NO in Step S53, and the process proceeds to Step S54. In step S54, the microcomputer 252 increases the transmission power by one step.

  On the other hand, when the output voltage value V exceeds the appropriate value, it is determined as YES in Step S53, and the process proceeds to Step S55. In step S55, the microcomputer 252 lowers the transmission power by one step.

  Specifically, for example, the following series of processes is executed as the process of step S54 or S55. That is, the microcomputer 252 generates control data including a change command for increasing / decreasing the transmission power by one step, and transmits the control data to the power transmission device 231 via the transmission circuit 253 and the antenna 254. Then, as described above, the power transmission device 231 increases / decreases the transmission power by one step by increasing / decreasing the gain of the amplification circuit 241 according to the control data.

  When such a series of processes is executed as the process of step S54 or S55, the process proceeds to step S56.

  In step S56, the microcomputer 252 determines whether or not an instruction to end the process is given.

  If the end of the process has not been instructed yet, it is determined as NO in step S56, the process returns to step S51, and the subsequent processes are repeated. That is, until the end of the process is instructed, the loop process of steps S51 to S56 is repeatedly executed to realize the transmission power variable control.

  Thereafter, when the end of the process is instructed, it is determined as YES in step S56, and the transmission power control process is ended.

  Thus, in the power transmission system 221 of the third embodiment, the transmission power control process is executed. Thereby, the transmitted power is automatically controlled so that the received power P becomes an appropriate value (required power). As a result, unnecessary radiation and useless power consumption can be prevented on the power receiving side, and adverse effects due to power shortage can be eliminated.

  In addition, when an obstacle enters between the power transmission side and the power reception side and a transmission loss occurs, even if the transmission distance does not change if the transmission power remains constant, the received power P decreases, There is also a possibility that an adverse effect due to shortage may occur. Therefore, as a countermeasure in such a case, it is preferable that the power transmission system 221 of the third embodiment is adopted to execute the transmission power control process.

<Other applications of the present invention>

  The first to third embodiments have been described above as the power transmission system to which the present invention is applied. However, the embodiment of the present invention is not particularly limited to the first to third embodiments, and may be any power transmission system to which the basic power transmission technique is applied.

  For example, as an embodiment of the present invention, a power transmission system to which any two or more of a resonance frequency variable technique, an oscillation frequency variable technique, and a transmission power variable technique are combined and applied can be employed.

  Further, for example, in the first to third embodiments, a method using radio waves is adopted as a method for transmitting and receiving control data between the power transmission side and the power reception side. However, the transmission / reception method is not particularly limited, and other methods such as a method using infrared rays can be employed. That is, as an embodiment of the present invention, a power transmission system to which an arbitrary transmission / reception technique is applied can be adopted.

  Furthermore, the series of processes described above can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software is installed from a program recording medium. This program is installed in, for example, a computer incorporated in dedicated hardware. Alternatively, this program is installed in, for example, a general-purpose personal computer that can execute various functions by installing various programs.

  FIG. 11 is a block diagram illustrating a hardware configuration example of a computer that executes the above-described series of processing by a program.

  In a computer, a CPU 301, a ROM (Read Only Memory) 302, and a RAM (Random Access Memory) 303 are connected to each other by a bus 304. An input / output interface 305 is further connected to the bus 304. The input / output interface 305 is connected to an input unit 306 including a keyboard, a mouse, and a microphone, an output unit 307 including a display and a speaker, and a storage unit 308 including a hard disk and a nonvolatile memory. Furthermore, the input / output interface 305 is connected to a communication unit 309 including a network interface, and a drive 310 that drives a removable medium 311 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

  In the computer configured as described above, the CPU 301 loads the program stored in the storage unit 308 to the RAM 303 via the input / output interface 305 and the bus 304 and executes the program, for example. Is performed. The program executed by the computer (CPU 301) is provided by being recorded on a removable medium 311 that is a magnetic disk (including a flexible disk), for example. The program is provided by being recorded on a removable medium 311 which is a package medium. As the package medium, an optical disc (CD-ROM (Compact Disc-Read Only Memory), DVD (Digital Versatile Disc), etc.), a magneto-optical disc, or a semiconductor memory is used. Alternatively, the program is provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting. The program can be installed in the storage unit 308 via the input / output interface 305 by attaching the removable medium 311 to the drive 310. Further, the program can be received by the communication unit 309 via a wired or wireless transmission medium and installed in the storage unit 308. In addition, the program can be installed in advance in the ROM 302 or the storage unit 308.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  In the present specification, the term “system” means an overall apparatus composed of a plurality of apparatuses and means.

  Embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 11 Power transmission system, 21 Power transmission apparatus, 22 Power reception apparatus, 31 Oscillation circuit, 32 Power transmission coil, 33 Power transmission side resonance circuit, 51 Power reception side resonance circuit, 52 Power reception coil, 53 Bridge rectifier circuit, 54 Smoothing capacitor, 81 Power transmission system , 91 power transmission device, 92 power reception device, 101 power transmission resonance circuit, 112 varicap, 121 power reception side resonance circuit, 123 microcomputer, 132 varicap, 161 power transmission system, 171 power transmission device, 172 power reception device, 192 phase synchronization circuit, 221 power transmission system, 231 power transmission device, 232 power reception device, 241 amplifier circuit, 242 transmission power control circuit, 243 microcomputer, 244 reception circuit, 252 microcomputer, 25 Transmission circuit, 301 CPU, 302 ROM, 303 RAM, 308 storage unit, 311 a removable media

Claims (18)

A power transmission unit that includes at least an oscillation unit and a resonance unit, and transmits power to the power receiving device according to a magnetic field resonance type power transmission method;
A power transmission apparatus comprising: control means for controlling at least one of the oscillation frequency of the oscillation means and the resonance frequency of the resonance means to maximize received power of the power reception apparatus. The control means includes
When a change command for changing at least one of the oscillation frequency and the resonance frequency is generated and transmitted by the power receiving device based on the received power,
Receiving the change instruction;
The power transmission device according to claim 1, wherein control is performed to change at least one of the oscillation frequency and the resonance frequency in accordance with the change command. The resonance means is configured so that the resonance frequency can be varied,
The change command is a command to change the resonance frequency,
The power transmission apparatus according to claim 2, wherein the control unit changes the resonance frequency in accordance with the change command. The resonance means has a varicap.
The power transmission device according to claim 3, wherein the control unit changes the resonance frequency by changing a voltage applied to the varicap. The oscillation means is configured such that the oscillation frequency can be varied,
The change command is a command to change the oscillation frequency,
The power transmission device according to claim 2, wherein the control unit changes the oscillation frequency in accordance with the change command. A power transmission device that includes at least an oscillation unit and a resonance unit, and transmits power to the power reception device according to a magnetic field resonance type power transmission method,
A power transmission method including a step of controlling the received power of the power receiving device to be maximized by changing at least one of an oscillation frequency of the oscillation means and a resonance frequency of the resonance means. Power receiving means for receiving the power using at least the power receiving side resonance means when the power is transmitted from a power transmission device that includes at least the oscillation means and the power transmission side resonance means and transmits power according to the magnetic field resonance type power transmission method When,
By changing at least one of the oscillation frequency of the oscillation means, the power transmission side resonance frequency of the power transmission side resonance means, and the power reception side resonance frequency of the power reception side resonance means, the received power in the power reception means is maximized. A power receiving device comprising: The power receiving side resonance means is configured to be able to vary the power receiving side resonance frequency,
The power receiving device according to claim 7, wherein the control unit measures the received power and changes the power receiving resonance frequency based on the measured value. The power receiving side resonance means has a varicap.
The power receiving device according to claim 8, wherein the control unit changes the power receiving side resonance frequency by changing a voltage applied to the varicap. The power transmission side resonance means of the power transmission device is configured such that the power transmission side resonance frequency can be varied,
The power receiving device according to claim 8, wherein the control unit further performs control to generate a change command for changing the power transmission side resonance frequency based on the measured value of the received power and transmit the change command to the power transmitting device. The oscillating means of the power transmission device is configured such that the oscillation frequency can be varied,
The power receiving device according to claim 7, wherein the control unit further performs control to generate a change command for changing the oscillation frequency based on the measured value of the received power and transmit the change command to the power transmitting device. A power receiving device that includes at least an oscillation unit and a power transmission side resonance unit, and that receives the power using at least a power reception side resonance unit when the power is transmitted from a power transmission device that transmits power according to a magnetic field resonance type power transmission method But,
By changing at least one of the oscillation frequency of the oscillation means, the power transmission side resonance frequency of the power transmission side resonance means, and the power reception side resonance frequency of the power reception side resonance means, the received power in the power reception device is maximized. A power receiving method including the step of controlling. A power transmission device including at least an oscillation unit and a power transmission side resonance unit, and transmitting power according to a magnetic field resonance type power transmission method;
A power receiving device that receives the power transmitted from the power transmitting device using at least a power receiving side resonance means; and
By changing at least one of the oscillation frequency of the oscillation means, the power transmission side resonance frequency of the power transmission side resonance means, and the power reception side resonance frequency of the power reception side resonance means, the received power in the power reception device is maximized. To control the power transmission system. Power transmission means for transmitting power to the power receiving device according to the magnetic field resonance type power transmission method;
A power transmission apparatus comprising: control means for controlling the power received by the power receiving apparatus by changing the power transmitted by the power transmission means. A power transmission device that transmits power to a power receiving device according to a magnetic resonance power transmission method,
A power transmission method including a step of controlling the received power of the power receiving device by changing the transmitted power of the power transmitting device. When the power has been transmitted from a power transmission device that transmits power according to a magnetic field resonance type power transmission method, power receiving means for receiving the power,
A power receiving apparatus comprising: control means for controlling the received power of the power receiving apparatus by changing the transmitted power of the power transmitting apparatus. When the power has been transmitted from a power transmission device that transmits power according to the magnetic field resonance type power transmission method, a power reception device that receives the power,
A power receiving method including a step of controlling the received power of the power receiving device by changing the transmitted power of the power transmitting device. A power transmission device that transmits power according to a magnetic field resonance type power transmission method;
A power receiving device that receives the power transmitted from the power transmitting device,
A power transmission system that controls the received power of the power receiving device by changing the transmitted power of the power transmitting device.

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